Some people think George W Bush did as much as he could to bring about Armageddon with his earlier interventions in the Middle East. But not the man himself, apparently. He has signed up for a fundraising event for the Messianic Jewish Bible Institute, an organisation which aims to promote the second coming by converting Jews to Christianity, and will speak today at their fundraiser in Irving, Texas.

Such "Messianic Jews" – who accept that Jesus was the promised Messiah – are loathed by most other Jews, and regarded with great suspicion by mainstream Christian denominations. If Jesus really was the promised Messiah, this would restore much of the traditional basis for Christian anti-semitism, which most Christians have struggled against for the last 50 years.

But a belief in the necessary conversion of the Jews still flourishes on the wilder shores of American Christianity. Portions of Biblical prophecy seem to require it. And there is widespread confusion among evangelicals about whether Israel is really a kind of America overseas – a recent poll for the Pew Foundation found that twice as many American Evangelicals as American Jews were unwavering in their support for Israel. This is something that successive Israeli governments have deliberately cultivated.

There is a delicious symbol of this confusion in the tat sold off the institute's website – a dog tag bearing the Star of David, with "Defender" written in the middle of it. The description reads:

God is raising up an army of believers to defend Israel, especially in these times more than ever. Wear this to represent your defense of Israel. In so doing, it will create conversations to give you opportunity to give a testimony of Isaiah 31:4-5.

Maybe that's the kind of pickup line that works better in Texas.

Bush himself famously described the war in Iraq as a "crusade" once, before it was pointed out to him that such language had unfortunate resonances in the Middle East. But the links between Zionism and Christianity go much further and deeper than that. The conversion of the Jews, and their restoration to Jerusalem, was a great enthusiasm among English evangelicals in Victorian times. Barbara Tuchman's marvellous book Bible And Sword chronicles some of the consequences.

It's fair to say that without the belief of Victorian upper class evangelical Englishmen – almost exactly the equivalents of George W Bush – there never would have been a Balfour Declaration. And without that declaration, there could not have been the Jewish immigration to Palestine that laid the foundations for the state of Israel.

Some people will see this as an example of the destructive craziness of religion, and perhaps it is, but it is also an example of the way in which theology is only powerful and important when it is wrapped up in identity. Because if there is one group that has suffered as a result of the establishment of the state of Israel and its support by Western Christian countries, it is the historic Christians of the Middle East – who are now the victims of persecution throughout the region and scapegoats of an angry nationalism. This is one reason why the churches with historic links to Palestinian Christians are much less pro-Israel than those which don't, like the majority of American Baptists.

In the end, what matters is not so much what you believe about God, as who you think you are. The upper classes of any global empire feel certain that God is on their side. The Bushes feel that now as surely as the Balfours did a hundred years ago – and two thousand years ago the Caesars believed that gods were actually among their family members. None of them were good news for the inhabitants of Palestine, and I can't help feeling that Bush and his Texan Zionists are not so close to Jesus as they are to the Romans who crucified him.